This invention relates to a master tool and more particularly to a torque multiplying wrench small enough to be hand held and capable of providing large increases in torque with minimum effort by the user.
Many presently available wrenches for providing high torque lack the ability to induce turning force in the plane of the nut or bolt. Furthermore, many of them suffer from one or more major limitations such as being very heavy and requiring bulky stabilizing reaction arms. Another drawback of existing torque multipliers is their relatively high cost and in many cases the need to have more than one person apply the tool.
Furthermore, new bolting technology is rapidly replacing riveting and welding methods in a variety of construction and engineering industries. Although the evolution of this technology has been rapid, the corresponding development of supporting tools has lagged far behind.
In my U.S. Pat. No. 4,506,567 issued on Mar. 26, 1985 I show a maximum capability wrench which was designed as a hand tool for mechanics, hobbyists, "do-it-yourselfers", and others, to remove, for example a stubborn nut, or to reach in places where the work to be performed does not permit rotation of the wrench itself. While the patented tool has proven to be useful under the particular set of circumstances described, it has turned out not to be adequate for the major applications described above. For these applications, the use of the chain drive produces an inadequate amount of torque multiplication. In addition, no provision is made to deal with the large reaction forces. Also, the patented tool does not permit repairs to be readily made by the user, a feature which might not be important for a small, inexpensive tool useful for relatively light applications. For the kinds of applications concerned about herein, the ability to make repairs in the field is an important advantage.
In my U.S. Pat. No. 4,928,558 issued on May 29, 1990, the problems associated with devices in use up to now for torque multiplication are largely overcome in a tool small and light enough to be hand held.
However, one of the concerns which appears in connection with the use of such a small tool capable of producing such large torque multiplication is the ability of the materials employed to transfer such large loads without excessive wear or outright failure in such circumstances.